Updated statistics with estimated new cases and deaths for 2017. Also revised text to state that among adults aged 50 years and older, the incidence rate has increased by 2% to 5% per year, however, data from 2004 to 2013 indicate that rates stabilized among individuals younger than 50 years; from 2005 to 2014, mortality rates stabilized among individuals 50 years and older and declined by 2.6% per year in individuals younger than 50 years.